Root Cellar
Food storage is an essential component of rural
survival. Enough food for one winter per person is a good start
and work up to storing one years worth. Ideally we want to grow
as much food as possible and buy or trade in bulk for the rest.
However all that food will become spoiled and useless in a short
time if not stored properly. The main concern is temperature, the
food cannot be allowed to freeze or reach room temperature.
Most food out of a garden will not keep unless canned,
dried or frozen. The natural keepers like potatoes, onion, garlic
and winter squash will last through most of the winter if kept in
a consistently cool, dark and dry environment. Dried food like sacks
of grain, nuts or dried fruit are more forgiving but they too will
last longer under those conditions. What we need is a root cellar.
|
|
Root cellars are the traditional food storage
structures, called as such because they were dug into the ground
or bermed up with earth to approximate a cave for temperature
control. Deep caves have a steady temperature year around, independent
of the air temperature outside whether a deep freeze or a withering
heat wave. |
Root cellars can be built below the house, in the
basement, outside as a stand alone structure or even as just a closed
off area of the house itself. The main concern being insulation
from the surrounding air temperature. Food is best kept in a dark,
dry and consistently cool area.
The pictures shown are of a modest root cellar built
into the north side of a house. It's a step down room about four
feet below floor level with a cement floor and knee wall bermed
up with earth on the outside. Above the knee wall and interior walls
are about a foot thick and insulated. It has two small windows for
light and venting. It works well as food and homemade wine storage
for two people. Note the thermometer on the wall for temperature
monitoring.
Cement floor root cellar on the north side of
the house with earth berm insulation. |
About 100 sq.' in size. |
Small window for light and vent.
|
An interesting fact is that a root cellar with an
insulated floor is more apt to freeze in extreme low temperatures
than an uninsulated floor such as plain dirt or cement. The reason
being the earth itself gives off constant heat which may not seem
like much but when the air temperature is zero, constant 40 F degrees
is warm by comparison. When insulation cuts off that warmth freezing
can occur.
If you have a un-seaworthy fiberglass boat that
you can't get rid of you can convert it into a root cellar as here.
Burying an ocean going container
maybe the fastest way of having a root cellar that is secure and
bug proof. Even a partial burial with enough earth berm thickness
on the sides and a mound on top would work. Another alternative
which maybe more cost effective is to enclose the container with
a straw bale shell, similar to building a straw bale house except
with the container serving as the frame. Cost effective in the fact
that the bales of straw would be cheaper to buy and have delivered
than hiring a backhoe or an excavating machine to dig a big hole,
devise a drainage system and placing the container in it. However
a free standing, above ground straw bale root cellar is the way
to go as the least expensive choice. If I did not have a container,
that would be my choice.
20' container planned for a root cellar.
|
Bales of straw are stacked like interlocking bricks
against exterior surfaces with steel rebars rammed through the bales
to add stability. The bottom row would be off the ground and the
outer surfaces sprayed with plaster or stucco for weather and bug
proofing. A roof, even a flat one, can be laid right on top without
snow load worries. Ideally the doors would face north with some
sort of an airlock or a thresh hold entrance so hot outside air
during summer will not rush in when opened.
Big straw bale in field. |
Straw close up. |
Straw should not have leaf or seeds. |
Average straw bales in our region measure 18"Wx14"Hx36"L
and weigh about 35lbs. and cost $1.50 to $4 a bale at a feed store,
the price fluctuating on the growing and harvesting weather. Approximately
200 bales are needed to cover a 20' ocean container. Buying in quantity
from a farmer directly should lower the price.
| Depending on how the straw is baled, the R
or the insulation value is close to R2 per inch or R36 for a
18" wide straw bale with about a 3.5 sq' coverage on the
14"x36" side. By comparison fiberglass insulation
of R38 is 12" thick with a unit coverage of 32 sq' at roughly
$1.00 sq'. |
|
The big disadvantage of fiberglass insulation is
that it requires a frame to hang it in. Any thickness beyond 6"
and the lumber required becomes cost prohibitive and any sort of
double wall construction would be tricky and time consuming. Foam
is the most expensive of insulating materials and also require some
sort of frame to set it in.
If I were to build a house, I would choose the straw
bale construction. I plan on using straw bales to convert my container
to an above ground root cellar and also to insulate a large above
ground water storage tank.
|
